Appendicular Skeleton....................

Skeleton System..Anatomy

1. Appendicular Skeleton BY Dr.V.S . Neharkar, M.Pharm,Ph.D Dept. of Pharmacology, RMDIPER,Chinchwad,Pune

2. APPENDICULAR SKELETON The appendicular skeleton consists of : 126 bones Allows us to move and manipulate objects Includes all bones besides axial skeleton The limbs The supportive girdles The Pectoral girdle with the upper limbs and the Pelvic girdle with the lower limb.

3. The Pectoral Girdle Also called the “shoulder girdle,” the pectoral girdle contains four (4) bones . It functions to anchor and support the upper extremities and serves as an important attachment site for a great number of muscles that help to move the arm . The bones of the pectoral girdle are as follows : 2 Clavicle ( Collar bone) 2 Scapula (Shoulder blade)

4. Clavicle The clavicle is the only long bone that lies in a horizontal position in the body. The clavicle has several important functions. First, anchored by muscles from above, it serves as a strut that extends laterally to support the scapula. This in turn holds the shoulder joint superiorly and laterally from the body trunk, allowing for maximal freedom of motion for the upper limb.

5. Scapula Also known as the “shoulder blades,” these contain the shallow sockets into which the head of the humerus fits . The scapula lies on the posterior aspect of the shoulder. It is supported by the clavicle , which also articulates with the humerus (arm bone) to form the shoulder joint . The scapula is a flat, triangular-shaped bone with a prominent ridge running across its posterior surface.

6. Bones of the Upper Limb The upper extremities or upper appendages, commonly called the “arms,” contain a total of sixty (60) bones from regions commonly called the “upper arm,” “forearm,” “wrist,” and “hand.” The bones of the upper extremities are… Humerus : 2 Radius: 2 Ulna: 2 Carpals: 16 Metacarpals: 10 Phalanges: 28

7. Humerus This is the bone of the upper arm. The head articulates with the glenoid cavity of the scapula, forming the shoulder joint . Distal to the head there are two roughened projections of bone, the greater and lesser tubercles, and between them there is a deep groove. The bicipital groove occupied by one of the tendons of the biceps muscle.

8. Radius & Ulna These are the two bones of the forearm. The ulna is longer than and medial to the radius and when the arm is in the anatomical position, i.e. with the palm of the hand facing forward, the two bones are parallel . They articulate with the humerus at the elbow joint, the carpal bones at the wrist joint and with each other at the proximal and distal radioulnar joints.

9. There are eight carpal bones arranged in two rows of four . From outside inwards they are: Carpal or wrist bones 5 1 2 3 4 4 3 2 1 6 5 7 8 Proximal row: 1 = Scaphoid 2 = Lunate 3 = Triangular 4 = Pisiform Distal row: 5 = Trapezium 6 = Trapezoid 7 = Capitate 8 = Hamate

10. These bones are closely fitted together and held in position by ligaments which allow a certain amount of movement between them . The bones of the proximal row are associated with the wrist joint and those of the distal row form joints with the metacarpal bones. Tendons of muscles lying in the forearm cross the wrist and are held close to the bones by strong fibrous bands. Carpal or wrist bones

11. Metacarpal – These five bones form the palm of the hand . They are numbered from the thumb side inwards. The proximal ends articulate with the carpal bones and the distal ends with the phalanges. Phalanges- There are 14 phalanges, three in each finger and two in the thumb . They articulate with the metacarpal bones and with each other. Metacarpal bones & Phalanges

12. The Lower Limb The lower extremities or lower appendages, and commonly called the “legs,” contain a total of sixty ( 62) bones from regions commonly called the Pelvic girdle, “thigh,” “shin,” “ankle,” and “foot .”. Pelvic Girdle Coxal , innominate, or hip bones (2 ) Lower Extremity Femur (2 ) Tibia (2) Fibula (2 ) Patella (2) Tarsals ( 14) Metatarsals (10 ) Phalanges (28)

13. The Pelvic Girdle The pelvic girdle , also called the “ pelvis ,” functions to support and protect the soft, vital organs of the abdominal cavity , provide a stable support for the trunk of the body , and to provide attachments for the lower extremities (the legs). Each hip bone consists of three fused bones these are- The Ilium The Ischium The Pubis a b c

14. The pelvic girdle (hip girdle) is formed by a single bone, the hip bone or coxal bone ( coxal = “hip”), which serves as the attachment point for each lower limb. Each hip bone, in turn, is firmly joined to the axial skeleton via its attachment to the sacrum of the vertebral column . The right and left hip bones also converge anteriorly to attach to each other. The bony pelvis is the entire structure formed by the two hip bones, the sacrum , and, attached inferiorly to the sacrum, & coccyx. The hip bone, or coxal bone , forms the pelvic girdle portion of the pelvis. The paired hip bones are the large, curved bones that form the lateral and anterior aspects of the pelvis . Each adult hip bone is formed by three separate bones that fuse together during the late teenage years. The Pelvic Girdle

15. The femur, or thigh bone, is the single bone of the thigh region It is the longest and strongest bone of the body , and accounts for approximately one-quarter of a person’s total height . The rounded, proximal end is the head of the femur , which articulates with the acetabulum of the hip bone to form the hip joint. Femur

16. The patella (kneecap) is largest sesamoid bone of the body A sesamoid bone is a bone that is incorporated into the tendon of a muscle where that tendon crosses a joint . The sesamoid bone articulates with the underlying bones to prevent damage to the muscle tendon due to rubbing against the bones during movements of the joint. Patella

17. The tibia (shin bone) is the medial bone of the leg and is larger than the fibula. The tibia is the main weight-bearing bone of the lower leg and the second longest bone of the body, after the femur . The medial side of the tibia is located immediately under the skin, allowing it to be easily palpated down the entire length of the medial leg. The distal extremity of the tibia forms the ankle joint with the talus and the fibula. The medial malleolus is a downward projection of bone medial to the ankle joint . The fibula is the long slender lateral bone in the leg . The head or upper extremity articulates with the lateral condyle of the tibia forming the proximal tibiofibular joint and the lower extremity articulates with the tibia to form distal tibiofibular joint. Tibia and fibula

18. The posterior half of the foot is formed by seven tarsal bones The most superior bone is the talus . This has a relatively square-shaped, upper surface that articulates with the tibia and fibula to form the ankle joint . Tarsal Bones 1 = Calcaneus (heel bone) 2 = Talus (ankle bone) 3 = Navicular 4 = Medial Cuneiform 5 = Intermediate Cuneiform 6 = Lateral Cuneiform 7 = Cuboid 1 2 3 4 7 6 5 4 3 2 1 Medial 5 Lateral

19. The anterior half of the foot is formed by the five metatarsal bones , which are located between the tarsal bones of the posterior foot and the phalanges of the toes . These elongated bones are numbered 1–5 , starting with the medial side of the foot. At their proximal ends they articulate with the tarsal bones and at their distal ends, with the phalanges . The enlarged distal head of the 1st metatarsal bone forms the 'ball' of the foot. Metatarsal Bones

20. There are 14 phalanges arranged in a similar manner to those in the fingers, i.e. two in the great toe and three in each of the other toes. Phalanges of the toes 1 2 3 4 7 6 5 4 3 2 1 Medial Phalanges

21. The arrangement of the bones of the foot is such that it is not a rigid structure. This point is well illustrated by comparing a normal foot with a 'flat‘ foot . The bones have a bridge-like arrangement and are supported by muscles and ligaments so that four arches are formed, a medial and lateral longitudinal arch and two transverse arches. Arches of the foot