Appendicular Skeleton

Summary

This informative lecture navigates through the components of the appendicular skeleton, emphasizing the distinctions and connections between different bone structures, including the humerus, radius, ulna, scapula, and femur. The lecture explains anatomical landmarks, such as tuberosities and articulations, in a detailed yet approachable manner. Laura Mastrangelo provides a comparative analysis of bones, like the difference between the axial and appendicular skeletons, and highlights the relevance of bone stability and mobility in joints, such as the shoulder and hip.

Highlights

• Understand the bone structures making up the arm - primarily focusing on the humerus, radius, and ulna. Each bone has specific articulations for mobility and function. 📚
• The scapula plays a crucial role in the shoulder's articulation with the humerus via the glenoid cavity, balancing mobility and stability. 💡
• The clavicle is an S-shaped bone in the appendicular skeleton contrasting with the rib in the axial skeleton, commonly tested in anatomy exams. 🎓
• Recognize the femur's size and structure, including the greater and lesser trochanters, as part of the thigh's skeletal anatomy. 🦵
• Understanding hands and feet can be simplified by memorizing the bone classification: carpal, metacarpal, and phalanges for hands, and tarsal, metatarsal, and phalanges for feet. 👣

Key Takeaways

• The humerus connects with both the ulna and radius to create a functional arm unit. 🩻
• The scapula features essential landmarks like the acromion process and glenoid fossa, critical to mobility. 🤸‍♀️
• The clavicle and ribs, while anatomically close, belong to different skeleton divisions - appendicular and axial, respectively. 🔍
• The femur, being the largest bone, offers a clear head, neck, and the distinctive linear aspera. 🦴
• Hands and feet have distinct naming conventions: carpals and tarsals, important for distinguishing between them during exams. 🙌

Overview

Welcome to a journey through the appendicular skeleton, led by Laura Mastrangelo. This week, as we delve into the anatomy of our limbs, expect to navigate through the arm, shoulder, and leg bones. From the upper arm humerus interacting with the ulna and radius, down to the leg with its mighty femur, learn how each bone articulates for motion and stability.

Laura's breakdown offers a clear view on separating axial from appendicular. The clavicle's s-curve distinguishes it from a rib, despite their close positioning in the body. Recognizing these differences is vital, especially when preparing for anatomy exams.

Finally, the lecture introduces the intricacies of the skeletal structure in our hands and feet. With differentiated bone groups like carpals in the wrist and tarsals in the feet, you will grasp how these bones uniquely function, supporting the complexity of locomotion and dexterity.

Chapters

• 00:00 - 00:30: Introduction to Appendicular Skeleton The chapter introduces the appendicular skeleton, focused on limbs and their bony attachments. Initially, there's a recap of the axial skeleton, which includes the head, neck, and trunk. The chapter then moves on to the appendicular skeleton, starting specifically with the upper limb. The first bone discussed is the humerus, noted humorously as not being 'funny,' despite the name. It is highlighted that there is only one bone in the arm, the humerus, and that important anatomical landmarks on this bone need to be identified.
• 00:30 - 02:00: Upper Limb Bones: Humerus and its Features The chapter focuses on the upper limb bones, specifically the humerus and its features.
• 02:00 - 03:00: Articulations of Humerus with Ulna and Radius The chapter explains the articulation point on the humerus known as the trochlea, which is relevant for its connection with the ulna, a bone of the forearm. This smooth, rounded surface facilitates the joint formation between these bones.
• 03:00 - 04:30: Humerus and Scapula Articulation The chapter discusses the anatomical articulation between the humerus and its neighboring bones, the ulna, and the radius. It highlights the unique feature of the ulna, called the trochlear notch, fitting into the smooth surface of the humerus. Additionally, the chapter hints at exploring the articulation of the humerus with the radius, emphasizing the importance of understanding these bone interactions.
• 04:30 - 06:00: Elbow and Forearm Bones: Ulna and Radius The chapter explains the articulation of the radius and ulna bones with the humerus in the elbow region. It focuses on the head of the radius and its articulation with the capitulum of the humerus. Additionally, it touches on the articulation of the ulna and emphasizes the importance of knowing specific areas of articulation on the humerus.
• 06:00 - 09:00: Hand and Wrist Bones This chapter discusses the anatomy of the hand and wrist bones. It details the deltoid tuberosity where the deltoid muscle attaches, the oon FAA which is a smooth shallow area, the Tropa, and the capitulum where the head of the radius articulates. The chapter emphasizes the importance of recognizing and remembering the five key features of these bones for academic purposes.
• 09:00 - 13:00: Lower Limb Bones: Femur and its Features The chapter explores the anatomy of the humoris, highlighting its articulation with both the Onna and the radius, as well as its connection to the scapula. The scapula itself is examined, with emphasis on identifying its parts, specifically the body and the acromion process. These elements are crucial for understanding the physiological functions and structural relationships within the shoulder area.
• 13:00 - 16:00: Tibia and Fibula: Leg Bones The chapter discusses the anatomy of the leg bones, specifically focusing on the tibia and fibula. While the transcript provided seems to be about the shoulder joint—discussing the glenoid cavity and the articulation with the humerus—it indicates the complexity of skeletal articulations and joint structures. The tibia and fibula, similar to the scapula-humerus in the shoulder, are critical in forming the knee and ankle joints, demonstrating the interconnectedness of skeletal anatomy.
• 16:00 - 19:00: Pelvic Girdle and Hip Articulation The chapter discusses the pelvic girdle and hip articulation, highlighting its significant mobility versus its lack of stability. The joint, while capable of various movements, is naturally shallow which makes it prone to dislocations. This is because the head of the humerus can easily separate from the glenoid fossa or cavity, emphasizing the trade-off between mobility and stability in this joint.
• 19:00 - 19:30: Conclusion and Additional Details The chapter provides insights into the structural anatomy of the shoulder and forearm, focusing on the joints and bones involved. It addresses the inherent instability of the shoulder joint and emphasizes the differences between the two primary bones of the forearm: the ulna and the radius. A mnemonic device is suggested to help remember the ulna's shape, comparing it to a 'u' or an ice cream scooper. It also hints at a terminology related to the ulna, although the term 'trar' seems to be unfinished.

Appendicular Skeleton Transcription

• 00:00 - 00:30 week we did the axial skeleton right and that is the head neck and trunk this week we're moving on to the appendicular which are their limbs are Limbs and their bony attachments okay Limbs and the Bony attachments so let's start with the Upper Limb okay we'll just move over here and I'll start with the bone of the arm the humoris there's nothing funny about this bone okay so there's one bone in our arm it is the humorus some of the anatomical landmark we need to see would
• 00:30 - 01:00 be the head of the humorus the deltoid tuberosity now a tuberosity is a protrusion and what do you think attaches to the deltoid tuberosity deltoid deltoid muscle right very good then there's there's actually five things on this bone there's quite a bit there's a depression on the humoris and this depression this shallow depression is called the oon FASA a FASA is a shallow depression and we see the oon faasa here
• 01:00 - 01:30 now one of the little things to notice with the little cues is that when you find the oon faosa straight up above from it this rounded surface here this soft and smooth surface is called the troia why is this important the tra is the place on the humoris where it will articulate or connect with the bone of the forearm the Ula and so it makes a very nice connection here here for this joint okay
• 01:30 - 02:00 what's kind of cool about the ulna is it has this little Notch that's taken out that's called the trar notch so the trolear notch fits right into this smooth surface the tra of the humorus that cool really kind of neat now in addition to the articulation of the humorus with the ulna there is an articulation with the radius right so we've got to try to figure out how that that fits here and
• 02:00 - 02:30 this is the head of the radius and it articulates at this very kind of smoothing area of the humorus and this part is called the capitulum so you're going to need to know that the capitulum is the place on the humorus where the head of the radius articulates and you're going to need to know that the tra is where is on the humorus where the trar notch of the oler articulates so let's go back to the humoris we see again the head this roughened area this
• 02:30 - 03:00 little deltoid tuberosity with the deltoid muscle attaches we also see the oon FAA that smooth shallow area then right below that this is the Tropa and then we have the capitulum where the head of the radius articulates there five things on this bone so there's quite a lot and you hope that I ask you the head cuz that's the easiest but you know there's other things here that you're going to have to know okay
• 03:00 - 03:30 now very interesting not only does the humoris articulate with the Onna and the radius it also articulates with the scapula right your shoulder so in this pile I do have a scapula so on our scapula we need to know this is called the body but that's I don't think it's even on our list we need to know this portion right here this is the a chroman or a chromian process right here and then that goes right into
• 03:30 - 04:00 the spine so a chromian and a chromian process and then this shallow depression is called the glenoid cavity or glenoid FAA because again faca is a shallow depression okay so this glenoid FASA articulates with the head of the humorus the head of the humorus articulates with the scapula at the glenoid faasa or glenoid cavity okay and this is your your shoulder um your shoulder joint now
• 04:00 - 04:30 the deal about this joint is it has lots and lots of Mobility okay we can do all different things with it but it's very shallow and hence it's highly unstable people dislocate this joint all the time right the head of the humoris comes away from the glenoid fossil or cavity so what we get in Mobility we lack stability in this joint very very very
• 04:30 - 05:00 unstable joint you know you can just see you can't barely get the head to stay there right so we've got scapula humoris nothing funny about that bone and we have the and the radius these are the two bones of the forearm they look distinctly different right totally different how you can remember the it's like a u right here right looks like a little icecream scooper allma and it has a u and that U is called again the trar
• 05:00 - 05:30 Notch right opposite the trar notch is this little bump on the Elna and that's called the oon process that's the very tip of your elbow okay that's the oon process so the tip of your elbow is part of your an that's all we have to know for this bone so the notch is on the inside the notch is on the inside the notch is going to articulate with the humoris very good and the radius very distinctly
• 05:30 - 06:00 looking bone its head is smooshed down this is the head right here where my tape is and it's smooshed okay then right underneath the head is the neck the neck of the radius and then right under that is the radial tuberosity this bump is another place for muscle attachment we've got the head the neck and then the radial tuberosity
• 06:00 - 06:30 now what's not on our list which I think is just a little interesting point is that at the end of both the radius and the ners are these little tips and they're called the styloid processes and these styloid processes are going to be right at the end of your forearm right before your wrist begins these two little points that you can feel before your hand or it's really your wrist those are the two little styloid processes from the radius and Alma one last bone here that is part of the brachial
• 06:30 - 07:00 uh girdle is the clavicle and it would be really nice if my clavicle just appeared here here is your pla I last last week when we did the axal skeleton I might have been like silly and told you if you have a rib you can talk on the rib did I tell you that and you it sounds so silly right because like everybody can get this rib but when the rib is there one part of the room and then this clavicle is on the other part of the room you're like oh my God which is a clavicle which is a rib they look
• 07:00 - 07:30 distinctly different you talk on a rib cuz it's c-shaped but a clavicle is s shaped you cannot talk on this you won't be able to get a good perception talk on that okay so your clavicle is a little s-shaped and that is part of the appendicular skeleton but your rib is c-shaped and that's part of your axial skeleton that's a great lecture exam question something like which of the following bones is in the axial skeleton then I give a list which of the
• 07:30 - 08:00 following bones is in the appendicular skeleton and I give you a list so rib and clavicle they seem like they'd be in the same region of your body but they're not this one rib is in axial and clavicle is in appendicular just you a little pointer there okay so now we can move on to the hand these are new brand new hands so they're very good some of the hands get old so what we're going to see with the hands are bones that make up our wrist wrist the palm of the hand and then
• 08:00 - 08:30 again the fingers so you don't have to know the individ individual bones for me you just need to know that all of these bones are called carpal so you have the bones of the wrist are carpal and then you have the bones of the hand the palm of your hand that's called metacarpal those are called metacarpal and then the bones of your fingers everybody knows right are called fangi so you've got carpal metacarpal
• 08:30 - 09:00 fanges easy right unless you get a foot now right now again they look totally different but test anxiety makes you wonder do you have a foot or a hand one good thing would be to hold it up to you I mean I have a big hand and even so this is just bigger than my this foot is bigger okay maybe for some of you men that wouldn't work but just take a look a second look at it you'll see your heel
• 09:00 - 09:30 and the arch in your foot but this is a foot and instead of having carpal metacarpal fanges what do we have we have tarel making our heel meta tarsals making your foot and then again fanges making up the toes so this is an easy one I hope you get this on your test hand or foot tap this small stick so you've got tels
• 09:30 - 10:00 metat torsal Banes so hand and foot make sure you can tell them apart which I know you can all right so moving on to the bones of the lower limbs okay we'll start with the big bone of our thigh this is the dinosaur bone nobody can get this wrong hold it up even in a big girl like me look this can't even be in my arm it's just too big this bone is your femur
• 10:00 - 10:30 your dinosaur bone and it's got some parts to it and some really good parts it's got a head a really nice head that's a head if I've ever seen a head of a bone this is the neck anatomical neck this big protrusion right here this is called the greater trochanter this is the lesser trochanter but I don't think the Lesser tranter is on our list but you can you can obviously tell the difference between greater troter and lesser troter so we've got head neck greater trochanter
• 10:30 - 11:00 and there's a a line going down this bone that is called the linear aspa I hope I'm right with that right down this bone linear aspa right here and then we have these two smooth surfaces at the distal portion of this bone and this is where the femur is going to articulate with the next bone the bone of the leg which is going to to be the tibia remember these softened
• 11:00 - 11:30 areas are called Condes we saw them on the occipital bone the occipital condil we saw them on the mandible the mandibular Condes and so these are called either the medial or the lateral condil so you know the head is medial so the side that the head is on this would be the medial cond and then that side opposite of the head would be the lateral Condon so this bone are of the thigh articulates with the tibia the bone of
• 11:30 - 12:00 the leg so what happens is your body weight is bashing on the poor head of the tibia you almost feel sorry for it and so what happens to that head look how flattened it becomes it's not a nice head like you see on the femur all your body weight goes onto the tibia the bone that is lateral in this case is the fibula and it actually does not articulate directly with the femur so none of the body weight is directly
• 12:00 - 12:30 transferred to your fibula okay just to your tibia so on your tibia we have this roughened area right here the proximal portion and this is called the tibial tuberosity this when you're shaving your legs and you Nick yourself which many of you know about that's because of the roughened portion of your tibial tuberosity um then right down the center this is called the anterior crest of the
• 12:30 - 13:00 tibia this line right here you can feel it when you hold it in your hand and then we have this portion right here this is called the lateral malis and this lateral malleolus is making off your ankle the medial portion of your ankle did I say lateral I meant I said lateral medial in the same sentence that was crazy so this is the medial molus making up the medial portion of your ankle because your tibia is your medial
• 13:00 - 13:30 bone your fibula is um lateral the fibula is great because the fibula you got you can't get this wrong this because it's like a baton okay but also the fibula only has one part that we need to know and that is the lateral malleolus which makes the lateral portion up of your ankle so that's cake you want this on your lab practical the bone with only one structure you can't get it wrong fibula lateral molis that's so much much easier than let's say the
• 13:30 - 14:00 femur with all the parts that you have to know but you're going to have the femur on the test even though you have to know like six things on it okay so and then I already showed you the foot which comes next in line one thing that I missed not on purpose but takes a lot of time to talk about would be the Ooa okay so this is part of your pelvic girdle you have two oxal bones Okay now what's really interesting about the oxa it is three three bones that are fused together so the larger bone right
• 14:00 - 14:30 here my hand is over this is the ilium it's the largest portion of the oxum then we have this section right here and this is the isum and then this part right here is the pubis so three bones fuse together actually all come together in the center all three bones are going to meet in the center and this cup in the center here this is called the acetabulum and this
• 14:30 - 15:00 is where the head of the femur articulates the head of the femur articulates with the ocoa at the acetabulum and this this is a ball and socket joint right this is what you think of of a great ball in socket the deal is with this joint there's not very much Mobility but it's highly stable you don't usually hear about people dislocating their hip they dislocate their shoulder way more right way before before they're going to dislocate their
• 15:00 - 15:30 hip because of this great ball on socket joint okay so the head of the femur will um articulate here in the acetabula okay there's a couple more things on this bone this is usually twice seen twice on my lab practicals we've got ilium isum pubis we've got the acetabulum then we have this roughened area on the isum called the isal tuberosity this is the portion that you're sitting on on your bony little butts it's the isal tuberosity and I
• 15:30 - 16:00 would always get confused like how can I tell the isum from the pubis so one of the things I try to look for is the pubis is more angular and pointy has more straight linear um lines so when you see the pubis I always think pointy pubis and then the isum is just a very rough area where you'd sit kind of looks like a a seesaw idea that you would sit on that this hole is called the apator foran this is a very big hole that we've
• 16:00 - 16:30 got here okay so we've got a lot of things going on in this bone not only the three bones that make it up then we have the um isal tuberosity the acetabulum the aptive faman and then when the two bones are together they do come together right between the pubis will be the pubis symphysis which is a piece of cartilage which I don't have with me these two don't even look like they go together they look so different but anyway it doesn't matter right between here would be the pubis
• 16:30 - 17:00 symphysis a piece of cartilage so you want to look at this B um I want to also mention this guy if anybody knows what this phone is this is the patella this is what you would think of as your kneecap it feels good in your hand like a stone okay patella and I think at this point I've hit all the bones in the appendicular skeleton okay I tell you a little story about the
• 17:00 - 17:30 patella later okay good all right