M2s4 Appendicular Skeleton Flashcards
Appendicular skeleton
-consists of upper and lower limbs
Upper limb appendicular skeleton
*look at goodnotes for images ‘
-30 bones extending from pectoral brindle to the hand
-in common terms, whole upper limb referred to as the “arm” however this is anatomically incorrect. Upper limb composed of the arm (shoulder to elbow) , forearm (elbow to wrist) and hand
Pectoral gridle
-connects upper limb to axial skeleton
-formed by:
Clavicle: an S-shaped bone. Joins with the manubrium of the sternum medically (proximally) and the scapula laterally (distally)
Scapula: triangular in shape. The unique features observed in the
-anterior surface - coracoid process, together with the acromion the coracoid process helps to stabilize the shoulder joint
-posterior surface - acromion and spine
Lateral surface - the glenoid fossa, which articulates with the head of the humerus (arm bone) to contribute to the shoulder joint
Arm - Humerus
-single main bone of the arm is the humerus
-articulates proximally with the glenoid fossa (shoulder blade) of the scapula to form the shoulder joint, and distally with the radius and ulna to form the elbow joint
Ball shaped structure of humerus is the head and face medically
-left of big bump is lesser and greater tubrecles (lateral) (opposite to head)
-below head is neck (anatomical neck in humerus as also find surgical neck which below tubrecles and where lots of humerus fractures occur that would need surgery)
-below neck is shaft which makes up majority of bone
-distol aspect of humerus has anterior portion with 2 depressions and 2 bones (lateral side round shaped structure called capetual which articulates with radius, on medial side spool shaped troclea which articulates with alna in medial side). Epicondials (lateral side and medial side)
Posterior portion with 1 depression called alegraton fossa which articulate with alegraton process of alna?
Laterally determines of bone left or right (if head medially and anterior 2 depressions 2 bumps and 1 fossa posteriorly, left bone)
Forearm
-composed of 2 bones:
Radius
-in anatomical position, the radius is laterally placed (thumb side) with reference to forearm
- has features of head (proximal end, round disc-shaped head which articulates with the capitulum (distal end) of the humerus and articulates with ulna) shaft, neck, distal end (wide adn flat, articulates with the carpal (wrist) bones to form the wrist joint, styloid process)
Ulna
-in anatomical position the ulna is medially placed (little finger side) with reference to the forearm
-looks like a pipe wrench
-has features Proximal end (articulates with distal end of humerus, olecranon - fits into the olecranon fossa of the humerus, trochlear notch - c-shaped depression which interlocks with the trochlea of the humerus) shaft, neck, head (distal end, styloid process)
Wrist and hand
-made mostly of smaller bones
Wrist - 8 carpal bones which are short bones
Palm/hand - 5 metacarpal bones which are long bones
Digits/ fingers - 14 phalanges which are long bones
-each finger has 3 phalanges with the exception of the thumb which only has 2
Lower limb appendicular skeleton
- look at good notes for photos
-arrangement similar to upper limb
-30 bones (or 31 if including innominate bone) from pelvic gridle to the foot
-term “leg” commonly used to refer to whole lower limb but this is not anatomically correct. The term refers to the area from the hip to the knee, while the rest of the lower limb is made up of the leg (knee to ankle), ankle and foot
Pelvic brindle
-attaches the lower limb to axial skeleton
-formed by hip (innominate) bones
-hip bones consist of ilium, ischium, and pubis
-note that the sacrum not included in the pelvic gridle
Ilium - largest bone in pelvic gridle And makes up superior portion of the pelvic gridle. The iliac crest can be touched easily by placing the hands on the hip, the point where the belt rests. Furthermore from the iliac crest at the back, one can see two dimples on both sides, these are PSIS of the hip bones
Ischium and pubis
-pubis fuses with both ilium and ischium
-unites with other pubic bone at the pubic symphysis (outbid symphysis made of fibrocartilage)
Features of pelvis bone
-bones of the pelvic girdle fuse to form 2 structures
Greater sciatic notch: located between the PIIS and the ischial spine. Allows the passage of major nerves and vessels from the pelvic cavity into the posterior region of the lower limb
Lesser sciatic notch: located between the ischial spine and the ischial tuberosity. Permits the passage of structures from the pelvic cavity to the genital region
Acetabulum: deep curved depression for articulation with the head of the femur
Obturator foramen: large opening on anterior and inferior aspect of each pelvic gridle for the passage of nerves and blood vessels
-the ischium and pubis contribute to the obturator foramen
-all three bones (ilium, ischium and pubis) contribute to the acetabulum
Thigh - Femur
-similar to upper arm, the thigh has a single bone - the femur
-features head (round shape structure that faces medially) , neck (below head, connect with rest of bone), shaft (forms majority of bone)
Proximal end of femur Head? - articulates the acetabulum of the pelvic gridle forming the hip joint. In addition to head and neck, the proximal end of the femur has other bumps/projections and ridges that serve as surfaces for muscle attachment
The distal end of femur - articulates with the tibia and patella (knee cap), forming the knee joint. Features include medial (medial side, longer and lower compared to lateral one) and lateral condyles (condyles are knuckle shape of bone that articulate with another bone) (these are the parts of the femur that form the knee joint with the tibia) and patellar (knee cap) surface which is the articular surface on the anterior aspects of the femur and forms a groove for the patella. Condyles on anterior side separated by smooth patellar surface but posterior seperated by inter condyle notch)
-largest bone in human body
-opposite to the head on the lateral side is the greater trocanter, and lessor trocanter higher down neck medially and see it from posterior)
-know left or right. Head medially, trocanter laterally and know smooth articular patellar surface on anterior side so left femur
Leg
-like forearm, comprised of 2 bones:
Tibia - only weight-bearing bone in leg and possesses the features including proximal end (medial and lateral condyles: articulate with the medial and lateral condyles of the femur, tibial tuberosity), shaft, distal end (medial malleolus)
Fibula - does not bear weight or transfer any weight, however lateral malleolus (distal tip of the fibula) provides lateral stability to the ankle joint. The fibula possess the features including proximal end (medial head which articulates with the tibia), neck, shaft, distal end (lateral mallelous)
-shin is the anterior border of tibia
-medial malleolus is the large bump that u can feel on the medial surface of the ankle
Ankle and foot
-many small bones
-tarsals are short, irregular bones while the metatarsals and phalanges although small, are classified as long bones
Ankle: 7 tarsal bones (short bones)
Foot: 5 metatarsal bones (long bones)
Digits/toes: 14 phalanges (long bones)
Pelvic grindle verse pectoral gridle
similarities:
-both connect the appendicular skeleton to axial skeleton
-glenoid fossa (pectoral gridle) and acetabulum (pelvic grindle) both articulate with the rounded head of long bones, the humerus and femur respectively
Differences:
-number and size of bones between girdles
-since lower limb plays critical role in bearing weight and locomotion, the pelvic gridle is larger and has more bones as compared to the pectoral gridle
Femur vs Humerus
Similarities:
-structure in terms of both having head, necks and medial and lateral condyles
Differences:
-femur larger in size as supports body’s weight (wider shaft, larger and more circular head, and larger condyles)
Leg vs forearm
Similarities:
-both 2 bones in the forearm and the leg, the radius/ulna and tibia/fibula respectively
Differences:
-size, bones in forearm (radius and ulna) are similar in size to one another but since the tibia is the weight-bearing bone in the lower leg, it is much wider than the fibula
