Appendicular Skeleton Includes: 126 bones Pectoral girdle (shoulder) Upper limbs Pelvic girdle Lower limbs

I. Pectoral (Shoulder) Girdle Function: to attach bones of upper limbs to axial skeleton Includes: Right and left clavicles (collarbones) Right and left scapulae (shoulder blades)

Clavicle Each clavicle is long, slender and S-shaped and transmits mechanical force from upper limb to the trunk Positioned horizontally above 1st rib Medial end of clavicle articulates with sternum Lateral end of clavicle articulates with acromion of scapula

Scapula Each scapula is large, flat and triangular Positioned in the posterior part of thorax The spine (sharp ridge) runs diagonally across the posterior surface of the body. The lateral end of the spine, the acromion, is the high point of the shoulder and articulates with the clavicle

Scapula The glenoid cavity is inferior to the acromion and articulates with the head of the humerus = shoulder joint The coracoid process is an anterior projection to which muscles attach

Upper limb 30 bones in each upper limb Humerus (arm) Ulna and radius (forearm) 8 carpals (wrist bones) 5 metacarpals (palm bones) 14 phalanges (finger bones)

Humerus Longest and largest bone of upper limb Head (proximal end) articulates with glenoid cavity of scapula Anatomical neck = groove just inferior to head Body contains V-shaped area called deltoid tuberosity = deltoid muscle attaches Capitulum (distal end) is a rounded knob that articulates with head of radius

Humerus Radial fossa = depression that receives head of radius when forearm is flexed Trochlea = spool shaped surface that articulates with ulna Coronoid fossa = depression that receives part of ulna when forearm is flexed Olecranon fossa = depression of back of bone that receives olecranon of ulna when forearm is extended

Ulna is medial (little finger side) bone of forearm and is longer than radius Olecranon is on proximal end of ulna and forms the prominence of elbow Coronoid process, together with olecranon, receives trochlea of humerus Radial notch = depression for head of radius Styloid process = distal end of ulna Ulna

Radius Radius is lateral (thumb side) of forearm Head (proximal end) or radius articulates with capitulum of humerus and radial notch of ulna Radial tuberosity = raised, rough area which attachment site for biceps brachii Distal end articulates with 3 carpal bones of wrist Styloid process at distal end Most common fracture in adults over 50

Carpals 8 carpal bones held together by ligaments Arranged in 2 rows (4 bones in each); named for their shape 4 of the bones form a cavity known as the carpal tunnel, through which tendons of the digits and thumb and the median nerve pass (narrowing of this tunnel compresses the median nerve = CT syndrome)

Metacarpals and phalanges Each metacarpal and phalanx consists of a proximal base, intermediate body, and distal head Metacarpals are numbered I – V (1-5) starting with lateral thumb Heads of metacarpals = knuckles There are 2 phalanges in thumb and 3 in each of the other 4 digits.

Pelvic (hip) Girdle Functions to provide support to vertebral column, protects pelvic organs, and attaches lower limbs to the axial skeleton Two coxal bones (hip bones) Pubic symphysis = anterior joint of hip bones

Pelvic Girdle pelvis = basin-like structure formed from the two hip bones and the sacrum and coccyx False pelvis = upper region; actually part of abdomen True pelvis = lower region; contains pelvic inlet

Each of the two coxal bones of a newborn is composed of 3 parts: Ilium (flank) = largest of three; iliac crest makes up upper border; greater sciatic notch makes up lower border (sciatic nerve passes through) Ischium = lower, posterior portion of hipbone. Hip bones

Hip bones Pubis = anterior and inferior part of hipbone All 3 bones have fused by age 23. Acetabulum = deep fossa where all 3 bones merge.; socket for head of femur Obturator foramen = formed by ischium and pubis; largest foramen of skeleton Hip bones

Lower limb 30 bones Femur (thigh) Patella (kneecap) Tibia and fibula (lower leg) 7 tarsals (ankle bones) 5 metatarsals 14 phalanges in foot

Femur Longest, heaviest, and strongest bone in body Proximally, the head of the femur articulates with acetabulum of hip bone to form hip joint. Neck of femur is region below head. “Broken hip” = fracture of neck of femur

Femur Greater trochanter = lateral projection ; attachment site for thigh and buttock muscles. Distally, the medial and lateral condyles of femur articulate with tibia; the patellar surface is located on the anterior surface of femur between the condyles and articulates with the patella.

Patella (knee cap) “little dish” Anterior to joint between femur and tibia (knee joint) Develops in the tendon of the quadriceps femoris

Patella (knee cap) Functions to increase leverage of the tendon, maintain position of the tendon, and protect the knee joint Patella glides up and down in the groove between the femoral condyles during flexion and extension.

Tibia Tibia = shin bone Tibia is the larger, medial bone of the lower leg and bears the body’s weight Proximal end of tibia expand into lateral and medial condyles which articulate with condyles of femur

Tibia Tibial tuberosity = raised anterior surface that is attachment site for patellar ligament Medial malleolus = articulates with talus of ankle ; prominence that can be felt on medial surface of ankle

Shin Splints Soreness or pain along the tibia Caused by inflammation of the periosteum brought on by repeated tugging of the attached muscles and tendons

Fibula Parallel and lateral to tibia Much smaller than tibia Head of fibula articulates with lateral condyle of tibia below knee joint Lateral malleous articulates with talus of ankle = prominence on lateral surface of ankle Fibular notch = articulates with tibia

Tarsus (ankle) Tarsals = 7 bones of the ankle Posterior: Talus (ankle bone); only bone of foot that articulates with fibula and tibia Calcaneus (heel bone); largest and strongest of tarsals Anterior: Cuboid Navicular 3 Cuneiform bones

Metatarsals and Phalanges Five bones called metatarsals are numbered I – V (1-5) from medial to lateral position Proximal base, intermediate body, and a distal head Big toe (hallux) has 2 phalanges; all other toes have 3 phalanges

Arches of Feet Bones of feet are arranged in 2 arches (longitudinal and transverse) which enable feet to support weight of body, provide distribution of body weight, provide leverage while walking. Falling arches (flat feet) can occur if the ligaments and tendons are weakened by excess weight, abnormal posture, or genetic predisposition.

Comparison of Female and Male Skeleton Bones of male are generally larger and heavier than female Tuberosities, lines and ridges are larger in male skeleton because certain muscles of the male are larger

Comparison of Female and Male Skeleton Female pelvis is wider and shallower than males. Acetabulum faces anteriorly in female and laterally in male

Comparison of Female and Male Skeleton Obturator foramen is oval in female and round in male Pubic arch is > 90 degrees in female and < 90 degrees male