UPPER LIMBS

 Upper Limb (p231) 30 bones form each upper limb A. Bones of the upper limb form the framework for the arm, forearm, and hand.

Figure 7.21

B. Humerus (fig 7.23, 7.25) 1. The humerus makes up the upper arm, extending from the scapula to the elbow. 2. It articulates with the scapulae at its head, with the radius at the capitulum, and with the ulna at the trochlea.

3. Other features: a. Head: fits into glenoid cavity b. Greater Tubercle—lateral side; and Lesser Tubercle— anterior side. Provide attachments for muscles

c. intertubercular groove—between 2 tubercles; where tendon passes (biceps brachi) d. surgical neck—below head & tubercles (where fractures commonly occur) e. Deltoid tuberosity—middle of shaft—V shaped

f. Condyles (2) rounded ends at distal ends of humerus (1) Capitulum (lateral, knoblike; articulates with the radius at elbow) (2) Trochlea (pulley shaped, on medial side; articulates with ulna)

g. Epicondyles—provide attachments for muscles & ligaments h. Coronoid fossa—between epicondyles. Receives coronoid process of the ulna when the elbow is bent i. Olecranon fossa—receives olecranon process of elbow when arm is straight

C. Radius (fig 7.24 & 7.25) a little shorter than the ulna

1. The radius is located on the thumb side of the forearm, extending from the elbow to the wrist. It crosses over the ulna when the palm is turned 2. head—proximal end (articulates with the capitulum of humerus) 3. head articulates with the radial notch of the ulna (allows rotation) 4. radial tuberosity—attachment for biceps muscle 5. styloid process—distal end—provides attachment for ligaments of wrist

D. Ulna--elbow to wrist; pinky finger side

1. The ulna is the longer of the two bones making up the forearm. Wrenchlike, and has a trochlear notch at proximal end that articulates with the humerus.

2. Other features: a. 2 processes on either side of notch: the olecranon process (attachment for muscles to straighten arm) & the coronoid process (to bend arm) b. Head—on lower end. Articulates with ulnar notch of radius c. Styloid process—distal end

E. Hand: wrist, framework (“palm”), 5 fingers 1. The wrist of the hand is made up of eight carpal bones bound into a carpus. (in 2 rows) 2. The framework of the hand is made up of five metacarpal bones. 3. The fingers are composed of three phalanges in each finger except the thumb, which lacks the middle phalanx. Total of 14 phalanges on each hand

SEATWORK:  What nerve is responsible for the tingly sensation you experience when you hit your funny bone?

ANSWER: THE ULNAR NERVE, LOCATED BEHIND THE MEDIAL EPICONDYLE

PELVIC GIRDLE & LOWER LIMBS

II. Pelvic Girdle A. The pelvic girdle supports and protects the lower abdominal and pelvic organs B. The pelvic girdle consists of the two coxal bones and the sacrum; it supports the trunk of the body on the lower limbs.

Figure 7.27a: Bones of the bony pelvis, p (a) Coxal bone (os coxae or hip bone) llium Sacroiliac joint Iliac fossa Pubic bone Ischium Sacrum Base of sacrum Sacral promontory Pelvic brim Ischial spine Acetabulum Pubic crest Pubic symphysis Iliac crest Coccyx Pubic arch

1. Each coxal bone is made up of three bones: the ilium, ischium, and the pubis, that are fused in the region of the acetabulum, the cuplike depression that articulates with the head of the femur.

Figure 7.27b: Bones of the bony pelvis, p (b) Ilium Ala Tubercle of the iliac crest Anterior gluteal line Posterior gluteal line Posterior superior iIiac spine Greater sciatic notch Posterior inferior iliac spine Ischial body Ischial spine Lesser sciatic notch Ischial tuberosity Ischium Ischial ramus Inferior gluteal line Acetabulum Pubic body Iliac crest Anterior superior iliac spine Anterior inferior iliac spine Pubis Inferior ramus of pubis

C. The ilium is the largest and most superior (uppermost) portion of the coxal bone and joins the sacrum at the sacroiliac joint on the posterior side.

Sacroiliac joint

1. Features of the ilium include the iliac crest, and anterior superior iliac spine.

D. The ischium forms the L- shaped portion that supports weight during sitting. 1. Features of the ischium include the ischial tuberosity and ischial spine.

a. Ischial tuberosity (points posteriorly and down) b. Ischial spine—can be used as a guide to determine pelvis size

E. The pubis comprises the anterior portion of the coxal bones 1. symphysis pubis—joins the 2 pubic bones at the midline 2. pubic arch—angle formed by 2 pubic bones

F. obturator foramen--largest foramen in skeleton

Lower Limb The bones of the lower limb provide the framework for the thigh, lower leg, and foot.

A. Femur 1. The femur, or thighbone, extends from the hip to the knee and is the longest bone in the body. 2. Its head articulates with the acetabulum of the coxal bone; it articulates with the tibia at the medial and lateral condyles.

3. Other features of the femur include a. fovea capitis—pit on head where ligament attaches b. neck--constriction below head c. greater trochanter--upper, lateral d. lesser trochanter—lower, medial

B. The patella (kneecap) 1. located in the tendon that passes over the knee 2. Flat, sesamoid bone which articulates with the femur on the anterior surface.

C. Tibia (largest bone in the lower leg) 1. On medial side 2. The tibia (shinbone) supports the weight of the body 3. the medial & lateral condyles--at the proximal end, articulate with the condyles of the femur 4. medial malleolus—inner side, distal end. Prominence for ligaments

D. Fibula 1. The fibula is a slender bone lying lateral to the tibia; it does not bear body weight 2. Head—proximal end 3. The lateral malleolus—distal end

E. Foot (ankle, instep, 5 toes) 1. The ankle is composed of seven tarsal bones, forming a tarsus. a. The talus moves freely & articulates with the tibia and fibula. b. The calcaneus (heel bone) supports the body weight.

2. The instep of the foot consists of five elongated metatarsal bones and provides an arch

3. Each toe is made up of three phalanges, with the exception of the great toe, which lacks a middle phalanx. (total of 14 on each foot). Great toe: nonopposable

STRUCTURE & FUNCTION:  Why are your feet segmented?  Couldn’t a single bone support your body weight and propel you forward when you walk or run?

ANSWER:  SEGMENTATION MAKES THE FOOT PLIABLE; THIS HELPS WHEN RUNNING OR WALKING ON UNEVEN GROUND