Chapter 9-The Appendicular Skeleton PDF

9.1 The Shoulder Girdle Two bones 1. Scapula - anchors the shoulder posteriorly - surrounded by muscles on both its anterior (deep) and posterior (superficial) Three landmark 1. superior border 2. medial border...

9.1 The Shoulder Girdle Two bones 1. Scapula - anchors the shoulder posteriorly - surrounded by muscles on both its anterior (deep) and posterior (superficial) Three landmark 1. superior border 2. medial border 3. lateral border > angles- two corners of the triangular scapula a. Superior angle - between superior and medial borders b. Inferior angle - between lateral and medial border - attachment point for several powerful muscles involved in shoulder and upper limb movements. c. glenoid cavity- between superior and lateral. Shallow depression cups the head of the humerus and proximal bone of the arm d. glenohumeral joint- formed by humerus and glenoid cavity Two prominent projections 1. coracoid process- Hook-like serves as attachment site for muscles of the anterior chest and arm (have strong ligaments to ties clavicle and coracoid process) 2. spine of the scapula- a long and prominent ridge 3. Acromion- bony tip of the superior shoulder region and articulates with the lateral end of the clavicle to form acromioclavicular joint clavicle, acromion, and spine of the scapula- form V-shaped bony line that provides for the attachment of neck and back muscles that act on the shoulder 2. Clavicle - S- shaped that connects the sternum to the shoulder - Long bone but the share the function with long bones and flat bones - Support scapula and hold the shoulder joint superiorly and laterally away from the rib cage, allowing for maximal freedom of motion for the arm - protect the underlying nerves and blood vessels sternal end of the clavicle- a triangular shape and articulates with the manubrium portion of the sternum sternoclavicular joint- allow mobility and o move in many directions acromial end of the clavicle- articulates with the acromion of the scapula, Bones of the Arm Three region a. Brachium - shoulder and elbow joints - Contains humerus  b. Antebrachium - elbow and wrist joints - Contains ulna and radius c. Hand - Contains 8 bones called carpal bones - thumb - 14 bones which is phalanx bone of the hand. 9.2a Humerus - Single bone of the upper arm - medially and articulates with the glenoid cavity to form the glenohumeral joint 9.2b Radius and Ulna > parallel supination and pronation - which allows us to flip the orientation of the hand. - accomplished by the rotation of the radial head, which causes the distal radius to move over and across the distal ulna. radiocarpal joint- distal end of the radius has a smooth surface for articulation with two carpal bones > The ulna does not technically contribute to the wrist joint; it is slightly shorter and separated from the carpal bones by a fibrocartilage disc 9.2c Bones of the Wrist and the Hand - Formed by a series of 8 small carpal bones which are arranged in two rows, forming a proximal row of 4 carpal bones and a distal row of 4 carpal bones Proximal row (lateral to medial) Thumb scaphoid (“boat-shaped”), Lunate (“moon-shaped” triquetrum (“three-cornered”) pisiform (“pea-shaped”) - articulates with the anterior surface of the triquetrum bone. - it forms the bony bump that can be felt at the medial base of your hand Distal bone (lateral to medial) trapezium (“table”) trapezoid (“resembles a table”) capitate (“head-shaped”) hamate (“hooked bone”) - Characterized by e hook of the hamate bone fingers and thumb - Contains 14 bones which is called a phalanx bone (plural phalanges) 9.3 The Pelvic Girdle and Pelvis the bones of the pelvis are strongly united to each other to form a largely immobile, weight-bearing structure important for stability during standing, walking, and running Os Coxae Adult os coxae- formed by 3 separated bones (ilium, ischium, pubis) that fuse 2gether during the late teenage yrs a. Ilium - Largest part of hip bone - United to the sacrum at the immobile sacroiliac joint (see Figure 9.11). iliac crest - superior ridge of ilium - Found in the hip anterior superior iliac spine- - felt at your anterolateral hip - attachment points for muscles of the thigh. anterior inferior iliac spine - Inferior to the anterior superior iliac spine is a rounded protuberance - attachment points for muscles of the thigh. posterior superior iliac spine - Produce a depression seen as a “dimple” located on the lower back - attachment points for the muscles and very strong ligaments that support the sacroiliac joint posterior inferior iliac spine. - located at the inferior end of a large, roughened area called the auricular surface of the ilium. - attachment points for the muscles and very strong ligaments that support the sacroiliac joint greater sciatic notch - provides a passageway for the very large sciatic nerve, which carries much of the innervation for the posterior leg. iliac fossa - bowl to hold the contents of the lower abdominal cavity b. ischium - it supports the body when sitting - forms the posteroinferior region of each hip bone ischial tuberosity (sit bones)- attachment for the posterior thigh muscles and also carries the weight of the body when sitting ischial ramus- a narrow segment of bone lesser sciatic notch- curved posterior margin of the ischium above the ischial tuberosity ischial spine- separating the lesser sciatic notch and greater sciatic notch c. pubis - forms the anterior portion of the hip bone  Pubis curves medially- joins to the pubis of the opposite hip bone called e pubic symphysis. pubic body- enlarged medial portion pubic tubercle- small bump located superiorly superior pubic ramus- reaches laterally from the pubic body to join the ilium. pectineal line-narrow ridge running along the superior margin pubic symphysis- join the pubic bodies of each bone inferior pubic ramus. subpubic angle- V-shape formed at the pubic symphysis 9.3b Features of the Whole Pelvis Acetabulum - a deep, cup-shaped cavity where ilium, pubis, and ischium is centrally form - hosts the rounded head of the femur to form the hip joint obturator foramen - large opening formed as the rami of the pubis and ischium meet - filled in by a layer of connective tissue - a large nerve passes through this space to reach the anterior leg pelvic brim, - formed by the pubic symphysis anteriorly, and the pectineal line of the pubis, the arcuate line of the ilium, and the sacral promontory (the anterior margin of the superior sacrum) posteriorly. greater pelvis (false pelvis) - occupied by portions of the small and large intestines - closely associated with the abdominal cavity lesser pelvis (true pelvis) - contains the bladder, the rectum, and the reproductive organ pelvic inlet - entrance to the pelvis. - important landmarks in birth as the fetus moves down from the greater pelvis into the lesser pelvis and then passes out of the body through the pelvic outlet. - narrowest parts of the passage and therefore present anatomical constraints to human birth. pelvic outlet. - inferior floor of the lesser pelvis - important landmarks in birth as the fetus moves down from the greater pelvis into the lesser pelvis and then passes out of the body through the pelvic outlet. - narrowest parts of the passage and therefore present anatomical constraints to human birth. Biological Sex and the Pelvis - Bigger bodies=wider pelvis=more muscle= more tension and force on the pelvis  estrogen - key physiological factor in determining shape of pelvis - Influence the ligaments that hold the pelvis bones - Pelvic in early teen is similar in shape but varying in the sizes. While pelvic in puberty starts to change due to estrogen signaling increases High level of estrogen - distance between the anterior superior iliac spines and the ischial tuberosities increases.Together these two changes increase the size of the pelvic outlet, which eases one anatomical constraint of childbirth - the subpubic angle is larger, typically greater than 80 degrees compared to an average of less than 70 degrees in individuals without high estrogen signaling. - female sacrum is wider, shorter, and less curved, and the sacral promontory projects less into the pelvic cavity, thus giving the female pelvic inlet (pelvic brim) a more rounded or oval shape compared to that of males - sciatic notch is narrower and deeper in biological males than the broader notch of biological female 9.4 Bones of the Leg Regions of legs 1. Thigh - Between the hip and knee joint, consist of femur (long bone) Femur - Longest and strongest bone that accounts for approximately ¼ ofl height. a. head of the femur- articulates with the acetabulum of the hip bone to form the hip joint. b. fovea capitis - tie the head of the femur to the acetabulum. - artery also uses this as an entry point into the femur. c. neck of the femur (femoral neck)- site of fracture d. greater trochanter- Multiple muscles that act across the hip joint ie attached which because of its projection from the femur, gives additional leverage to these muscles. e. lesser trochanter- single powerful muscle is attached f. intertrochanteric line g. gluteal tuberosity- roughened area extending inferiorly from the greater trochanter h. linea aspera (“rough line”)- roughened ridge that passes distally along the posterior side of the midfemur i. Epicondyles- rough bony expansions j. lateral epicondyle of the femur- attachment point for muscles (attachment sites for muscles and supporting ligaments of the knee)  k. lateral condyle of the femur- lateral and superior in lateral epicondyle (articulate with the tibia to form the knee joint.) l. medial condyle of the femur- smooth articulating region in medial (articulate with the tibia to form the knee joint.) m. medial epicondyle of the femur- rough outer side (attachment sites for muscles and supporting ligaments of the knee) n. intercondylar fossa- depression that seperates medial and lateral condyles o. patellar surface-the smooth surfaces of the condyles join together to form a wide groove (articulation with the patella bone) 2. Lower leg - Has 2 parallel bones a. Tibia (medial side of the leg) - larger and weight bearing - for muscle attachments a. medial condyle of the tibia and the lateral condyle of the tibia- two smooth, flat proximal surfaces b. b. Fibula (lateral)- thinner bone patella/kneecap- largest sesamoid bone that articulates with distal femur - Incorporate inpatella is the one sesamoid bone that is universal to all humans (and many other animals).to the tendon of a muscle - prevents rubbing of the muscle tendon against the distal femur - lifts the tendon away from the knee joint, which increases the leverage power of the quadriceps femoris (thigh) muscle it attaches to. The patella does not articulate with the tibia. Posterior foot and ankle Posterior foot- 7 bones, known as tarsal bone a. Mid-foot- contains 5 long metatarsals b. Toes- contains 14 small phalanx Ankle- formed by 2 bones 9.4c Tibia and Fibula 347 9.4d Bones of the Foot a. Talus- most superior bone b. ankle joint- formed from talus by fitting its relatively square-shaped, upper surface into an arch created by the distal ends of the tibia and fibul c. Calcaneus- heel bone and the largest bone of the foot. d. navicular bone-proximal row of tarsal bones distal row of tarsal bones- articulate with the metatarsals. a. Cuboid bone > medial cuneiform > intermediate cuneiform > lateral cuneiform. Toes a. Hallux- big toe that has 2 phalanx bones b. The remaining toes have all proximal, middle, and distal phalanges c. interphalangeal joint- joint between adjacent phalanx bones