Human Anatomy Chapter 5

Human Anatomy for Nursing Students

• Course taught by Dr. Fatima Aljamal
• Academic year 2024-2025

Chapter 5: Axial and Appendicular Skeleton

• The skeleton is divided into two parts: axial and appendicular
• Axial skeleton includes 80 bones
• Appendicular skeleton includes 126 bones

Axial Skeleton

• Forms the central axis of the body
• Includes skull, vertebral column, and thoracic cage
• Protects vital organs: brain, spinal cord, heart, and lungs
• Attachment site for muscles moving the head, neck, and back, as well as some limb muscles
• Divided into regions (skull, vertebral column, and thoracic cage).

1. Skull Bones (29 Bones)

• Cranium (8 bones): frontal, parietal (2), temporal (2), occipital, sphenoid, ethmoid
• Facial (14 bones): zygomatic (2), maxillae (2), nasal (2), lacrimal (2), palatine (2), inferior conchae (2), vomer, mandible (1)

Skull Cavity & Sinuses

• Hollow spaces within the skull and facial bones surrounding the nose
• Four pairs of sinuses: maxillary, frontal, ethmoid, and sphenoid
• Collectively called paranasal sinuses

2. Vertebral Column

• Sequence of vertebrae (singular: vertebra) and intervertebral discs
• Originally 33 vertebrae, reduced to 24 plus sacrum and coccyx
• Divided into 5 regions: cervical (C1-C7), thoracic (T1-T12), lumbar (L1-L5), sacrum (5 fused vertebrae), coccyx (4 fused vertebrae)
• Spinal curves increase strength, flexibility, and shock absorption
• Four curves: cervical, thoracic, lumbar, and pelvic

3. Vertebral General Structure

• Typical vertebra consists of a body, vertebral arch, seven processes, three foramens, and facets

3. Thoracic Cage

• Rib cage forms the thorax
• Composed of 12 pairs of ribs, costal cartilages, and the sternum
• Ribs attach posteriorly to 12 thoracic vertebrae (T1-T12)

Appendicular Skeleton

• Peripheral skeleton (126 bones)
• Composed of the pectoral girdle, upper limb bones, pelvic girdle, and lower limb bones

1. Pectoral Girdle (Shoulder Girdle)

• Two bones: clavicle and scapula
• Attaches the upper limb to the axial skeleton
• Provides attachment for shoulder and upper limb muscles
• Forms the cervico-axillary canal

2. Bones of the Upper Limb

• Divided into arm (humerus), forearm (ulna and radius), wrist (carpal bones), and hand (metacarpals and phalanges)
• Three main joints: shoulder (glenohumeral), elbow, and wrist

3. Wrist (Carpal)

• Scaphoid, lunate, triquetral, pisiform, trapezium, trapezoid, capitate, and hamate
• Proximal and distal rows
• Radiocarpal, midcarpal, and carpometacarpal joints
• Carpal tunnel forms

4. Hand (Metacarpal & Phalanges)

• 5 metacarpals, 14 phalanges
• Thumb and other fingers have proximal, middle, and distal phalanges
• Carpometacarpal, carpophalangeal, and interphalangeal joints
• Joints connect the phalanges of the fingers

3. Pelvic Girdle

• Formed by a single hip bone (attaching lower limb to axial skeleton via sacroiliac joint)
• Attaches lower limbs to the axial skeleton
• Transmits weight of upper body to lower limbs
• Supports pelvic visceral organs
• Consists of ilium, ischium, and pubis

4. Bones of the Lower Limb

• Divided into thigh (femur), leg (tibia and fibula), ankle (tarsal bones), and foot (metatarsals and phalanges)
• Three main joints: hip, knee, and ankle

Foot (Metatarsal & Phalanges)

• 5 metatarsals (numbered 1-5)
• 14 phalanges (big toe (2) and other toes (3) )
• Parts of the foot include arches and the transverse arch