��General Anatomy� The Skeletal System 3� Appendicular Skeleton ����

The Appendicular Skeleton

• Pectoral girdle
• Attaches the upper limbs to the trunk
• Pelvic girdle
• Attaches the lower limbs to the trunk
• Upper and lower limbs differ in function
• But share the same structural plan

Articulated Pectoral Girdle

Appendicular Skeleton

• Upper extremity
• Consists of the bones of the shoulder girdle, upper arm, lower arm, wrist, and hand
• Shoulder girdle
• Made up of scapula and clavicle
• Clavicle forms only bony joint with trunk, the sternoclavicular joint
• At its distal end, clavicle articulates with the acromion process of the scapula

Pectoral Girdle

• Shoulder girdle
• Clavicles
• Scapulae
• Supports upper limbs

Clavicles

• Articulate with the manubrium
• Articulate with scapulae (acromion process)

Scapulae

• Spine
• Supraspinous fossa
• Infraspinous fossa
• Subscapular fossa

• Acromion process
• Coracoid process
• Glenoid cavity

The Upper Limb

• 30 bones form each upper limb
• Grouped into bones of the
• Arm
• Forearm
• Hand

Upper Limb

• Humerus
• Radius
• Ulna
• Carpals
• Metacarpals
• Phalanges

Humerus

• The long bone of the upper arm
• Articulates proximally with the glenoid fossa of the scapula and distally with the radius and ulna

Humerus

• Head
• Greater tubercle
• Lesser tubercle
• Intertubercular groove.
• Anatomical neck
• Surgical neck
• Deltoid tuberosity
• Capitulum
• Trochlea
• Coronoid fossa
• Olecranon fossa

• Long bone found on thumb side of forearm.
• Articulates proximally with capitulum of humerus to form the elbow joint and radial notch of ulna to form the proximal radio-ulnar joint.
• Articulates distally with scaphoid and lunate carpals to form the wrist joint and with head of ulna to form the distal radio-ulnar joint.

Radius

Radius

• Lateral forearm bone
• Head
• Radial tuberosity
• Styloid process

• Long bone found on little finger side of forearm.
• Articulates proximally with humerus to form the elbow joint and radius to form the proximal radio-ulnar joint.
• Articulates distally with a fibrocartilaginous disc that separates it from the carpal bones, so the ulna does not share in the formation of the wrist joint.

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Ulna

Ulna

• Medial bone of the forearm
• Trochlear notch
• Olecranon process
• Coronoid process
• Head
• Styloid process

Wrist and Hand

• Carpals (16)
• Trapezium
• Trapezoid
• Capitate
• Hamate
• Scaphoid
• Lunate
• Triquetrum
• Pisiform

• Metacarpals (10)

• Phalanges (28)
• Proximal phalanx
• Middle phalanx
• Distal phalanx

Distal Row

Proximal Row

Appendicular Skeleton

• Lower extremity

Consists of the bones of:

• Hip
• Thigh
• Leg
• Ankle
• Foot

Pelvis

• The adult pelvis is composed of four bones:
• the sacrum, the coccyx, and the right and left ossa coxae.

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• It protects and supports the viscera in the inferior part of the ventral body cavity.

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• Pelvic girdle refers to the left and right ossa coxae only.

Os Coxae

• Commonly referred to as the “hip bone” or innominate bone.
• Each is formed from three separate bones:
1. The ilium
2. The ischium
3. The pubis
• Each articulates posteriorly with the sacrum at the sacroiliac joint.

Pelvic Girdle

• Coxae (2).
• Supports trunk of body.
• Protects viscera.

Coxae

• Hip bones
• Acetabulum
• Ilium
• Iliac crest
• Iliac spines
• Greater sciatic notch
• Ischium
• Ischial spine
• Lesser sciatic notch
• Ischial tuberosity
• Pubis
• Obturator foramen
• Symphysis pubis
• Pubic arch

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Greater and Lesser Pelvis

Greater Pelvis (False Pelvis):

• Lumbar vertebrae posteriorly
• Iliac bones laterally
• Abdominal wall anteriorly

Lesser Pelvis (True Pelvis):

• Sacrum and coccyx posteriorly
• Lower ilium, ischium, and pubic bones laterally and anteriorly

Male and Female Pelvis

Female (Picture a)

• Iliac bones are more flared
• Broader hips
• Pubic arch angle is greater
• More distance between ischial spines and ischial tuberosities
• Sacral curvature shorter and flatter
• Lighter bones

Lower Limb

• Femur
• Patella
• Tibia
• Fibula
• Tarsals
• Metatarsals
• Phalanges

Femur

• The longest bone of body
• Head
• Fovea capitis
• Neck
• Greater trochanter
• Lesser trochanter
• Linea aspera
• Condyles
• Epicondyles

Patella

• The knee cap
• Anterior surface of knee
• A flat sesamoid bone located in a tendon

Tibia

• Shin bone
• Medial to fibula
• Condyles
• Tibial tuberosity
• Anterior crest
• Medial malleolus

Fibula

• Lateral to tibia
• Long, slender
• Head
• Lateral malleolus
• Does not bear any body weight

Ankle & Foot

• Tarsals (14)
• Calcaneus
• Talus
• Navicular
• Cuboid
• Lateral cuneiform
• Intermediate cuneiform
• Medial cuneiform

• Metatarsals (10)

• Phalanges (28)
• Proximal
• Middle
• Distal

Ankle and Foot

Arches of the Foot

• The sole of the foot does not rest flat on the ground.
• Helps it support the weight of the body.
• Ensures that the blood vessels and nerves on the sole of the foot are not pinched when standing.

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Arches of the Foot

• Medial longitudinal arch extends from the heel to the big toe.
• Lateral longitudinal arch is not as high as the medial longitudinal arch.
• Transverse arch runs perpendicular to the longitudinal arches.

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Pes planus (Flat Foot)

• A condition in which the medial longitudinal arch is depressed or collapsed.
• As a result, the forefoot is displaced laterally.
• The head of the talus is no longer supported.
• The causes of flat foot can be congenital or acquired.