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Home , Trochlea of humerus

Skeletal System -Appendicular System

Chapter 8 Part B Skeleton - Divisions

Total number of : 206

Divided into two major subdivisions: Axial system….blue Appendicular system….tan Axial system: Composed of bones that form the axis of the body. 80 bones. Appendicular system: Composed of bones that form The limbs. The bones that attach the limbs to the axial. 126 bones.

Practice…Practice…Practice…Practice…Practice!! Appendicular Skeleton

Appendicular system:

Pectoral girdle 4 bones Upper extremity 60 bones Pelvic girdle 2 bones Lower extremity 60 bones 126 bones Appendicular Skeleton

Appendicular system:

Pectoral girdle 4 bones Upper extremity 60 bones Pelvic girdle 2 bones Lower extremity 60 bones 126 bones Upper Extremity/Limb

Upper limbs/extremities are composed of 60 bones…30 bones in each limb:

Upperarm – – and Wrist – Carpals – Metacarpals in palm – Phalanges in fingers and thumb Upper Extremity/Limb - Humerus

Body/Shaft

Humerus: long . Has 3 regions: Proximal end articulates with glenoid cavity of . Distal end articulates with radius and ulna. Body/Shaft: diaphysis between proximal and distal ends. Has rough surface – …for deltoid muscle attachment. Upper Extremity/Limb - Humerus

Body/Shaft

Humerus - Proximal end: Head: rounded projection  fits into glenoid cavity of scapula. Greater and lesser tubercles: projections next to the head  for muscle attachment. Intertubercular sulcus: groove between the tubercles  accommodates tendon of an muscle. Upper Extremity/Limb - Humerus

Body/Shaft

Humerus - Distal end: Anterior surface: Capitulum: small, rounded knob  articulates with proximal end of radius of forearm. Trochlea: spool-shaped structure  articulates with proximal end of ulna of forearm. Posterior surface: fossa: depression  where olecranon of ulna fits. Medial/Lateral epicondyles: rough surfaces for muscle attachment. Upper Extremity/Limb - Radius

Capitulum

Radius head

Radial tuberosity

Anterior view

Radius: lateral bone of the forearm. Proximal end: Radius Head: flat disc  articulates with capitulum of humerus.  articulates with of ulna (proximal radioulnar joint) : rough surface for upper arm muscle attachment.

Distal end:  ulnar notch of radius articulates with ulnar head (distal radioulnar joint)  articulates with some of the carpals in the wrist. Styloid process: pointed projection  for wrist muscle attachment. Upper Extremity/Limb - Ulna

Humerus

Posterior view

Ulna: medial bone of the forearm. Proximal end: articulates with distal end of humerus and proximal end of radius. Olecranon process (pointed tip of )  fits into in the posterior surface of humerus (extension). : depression  into which trochlea of humerus fits. Coronoid process  fits into the coronoid fossa in the anterior surface of humerus (flexion). Distal end: articulates with distal end of radius and some of the carpals in the wrist. Head of ulna: articulates with ulnar notch at distal end of radius. Styloid process of ulna: pointed projection  for wrist ligaments attachment.

Elbow joint is formed by articulation of 3 bones: Humerus, Radius, Ulna. Upper Extremity/Limb – Wrist/ Carpus

Wrist is made of 8 short bones - carpals. Carpals are arranged in 2 rows: Proximal row articulate with radius:- lateral to medial order-Scaphoid, Lunate, Triquetrum, Pisiform Distal row articulate with metacarpals of the palm:- lateral to medial order-, Trapezoid, Capitate, Hamate “Sam Likes To Push The Toy Car Hard” Q. Which of the following bones is NOT found in the proximal row of carpals? Upper Extremity/Limb – Hand

Hand is divided into: Palm – with metacarpals. Fingers– has phalanges. Palm: made of 5 long bones- metacarpals- lateral to medial- Roman Numerals I-V Each metacarpal has: Proximal end – base - articulates with the carpals. Distal end – head - articulates with proximal end of phalanges…form “knuckles”. Upper Extremity/Limb – Hand

Each hand has 14 long bones- phalanges Pollex/Thumb- has 2 phalanges (proximal and distal) Other four fingers- has 3 phalanges each (proximal, middle, distal)

Q) Bill accidentally fractures his first distal phalanx with a hammer. Which finger is broken? Appendicular Skeleton

Appendicular system:

Pectoral girdle 4 bones Upper extremity 60 bones Pelvic girdle 2 bones Lower extremity 60 bones 126 bones Pelvic Girdle – Coxal Bones Sacrum

Coccyx

Ilium

Coxal/ Hip Pubis bone

Ischium

Pevic girdle: Attaches lower extremity/limb to the axial system. Consists of 2 flat bones – coxal/pelvic/hip bones Before birth  Each coxal bone is composed of 3 bones - Ilium, Ischium, Pubis. After birth  the 3 bones completely fuse  no visible sutures in adult. Posteriorly: coxal bones (ilium) articulate with sacrum. Anteriorly: coxal bones (pubis) articulate with each other with the help of fibrocartilage disc…pubic symphysis. Angle formed at the symphysis…pubic arch. Ischium: Forms posterior inferior part of the coxal bones Pelvic Girdle – Coxal Bones

Obturator canal

Obturator membrane

Iliac crest: Prominent ridge on the ilium-attachment of muscles and ligaments. Acetabulum: a concave socket on lateral surface of hip bone-formed by fusion of all 3 bones  articulates with head of the femur (thigh bone). Obturator foramen: a large hole formed by ischium and pubis  covered by a obturator membrane  muscle attachment. Obturator canal:- for passage of blood vessels and nerves PELVIS

Pelvic girdle: consist of 2 coxal/hip bones Pelvis: Coxal bones + Sacrum and Coccyx False pelvis: the outer rim of the pelvis. True pelvis: the inner rim of the pelvis. Pelvic brim: bony edge of the true pelvis. Pelvic inlet: superior opening for newborn to enter…outlined by true pelvis. Pelvic outlet: inferior opening for newborn to exit…limited by coccyx and ischial spines. Pelvis – Male vs. Female

Male Pelvis PELVIS Female Pelvis Narrower, rougher, more robust General Appearance Broader, smoother, less robust

More vertical; extends farther Ilium Less vertical; less extension superior to sacroiliac joint superior to sacral articulation

Long, narrow triangle Sacrum Broad, short with pronounced triangle with less sacral curvature sacral curvature

Deeper Iliac fossa Shallower

Narrower, Pelvic inlet Open, heart circular shaped shaped

Narrow Pelvic outlet Enlarged

Points Coccyx Points anteriorly inferiorly

Directed Acetabulum Faces slightly laterally anteriorly

Oval Obturator foramen Triangular

Under 90º Pubic angle 100º or more

OTHER

Heavier Bone weight Lighter

More prominent Bone markings Less prominent Pelvis – Male vs. Female Appendicular Skeleton

Appendicular system:

Pectoral girdle 4 bones Upper extremity 60 bones Pelvic girdle 2 bones Lower extremity 60 bones 126 bones Lower Extremity/Limb

Lower limbs/extremities are composed of 60 bones…30 bones in each limb:

Thigh – Femur Lowerleg – Tibia and Fibula Ankle – Tarsals Foot – Metatarsals in foot – Phalanges in the toes Lower Extremity/Limb - Femur

Body/Shaft

Femur – Longest and heaviest bone in the body. Proximal end: Head: rounded projection  fits into acetabulum of coxal bone (pelvic girdle). Greater and lesser trochanters: projections next to the head  for muscle attachment. Body/Shaft: diaphysis between proximal and distal ends. Has rough surface – gluteal tuberosity …for buttock muscle attachment. Lower Extremity/Limb - Femur

Posterior surface

Femur - Distal end: Anterior surface: Patellar surface: where patella (knee cap) sits. Posterior surface: Medial and lateral : 2 rounded surfaces  articulate with proximal end of tibia. Intercondylar fossa: accommodates tendon of the lower leg muscle. Medial/Lateral epicondyles: rough surfaces for ligament attachment. Lower Extremity/Limb - Patella

Patella: Triangular, flat bone. Placed on distal end of femur…patellar surface. Wrapped inside the tendon of the thigh muscle – sesmoid bone  tendon continues as patellar ligament  to anchor the patella to tibia.

Patellar fracture: results in damage of tendon/ ligament  difficulty in leg movement. Lower Extremity/Limb - Tibia

Lateral Medial condyle of Femur of Femur

of Tibia of Tibia

Tibia: medial bone of the leg. Proximal end: articulates with distal end of femur and proximal end of fibula. Lateral/Medial condyles: flat surfaces  articulates with lateral/medial condyles of femur. Tibial tuberosity: rough surface for thigh muscle attachment and patellar ligament.

Distal end: articulates with distal end of fibula and some of the tarsals in the ankle. Medial malleolus: bumpy projection  seen on medial surface of the ankle – supports ankle joint. Lower Extremity/Limb - Fibula

Fibula: lateral bone of the leg. Proximal end: articulates with proximal end of tibia. Head: articulates with tibia  superior tibiofibular joint. Distal end: articulates with distal end of tibia and some of the tarsals in the ankle. Lateral malleolus: bumpy projection  seen on lateral surface of ankle – articulates with distal end of tibia and supports ankle joint. Lower Extremity/Limb – Ankle/Tarsus

LATERAL

MEDIAL Ankle is made of 7 short bones - tarsals. 1) Talus- transmits the body weight from tibia toward the toes. 2) Calcaneus- Heel bone-Largest tarsal bone-when standing normally-weight transmitted from tibia to talus- to calcaneus-to the ground. 3) Cuboid- on the lateral side of ankle 4) Navicular-on the medial side of ankle Superior view, 5) Cuneiform bones-Medial, Intermediate, Lateral right foot “Tom Can Control Not Much In Life” Lower Extremity/Limb - Foot

Medial

Medial Lateral

Lateral

Foot: made of 5 long bones- metatarsals-from medial to lateral-I to V Each metatarsal has: Proximal end – base - articulates with the tarsals. Distal end – head - articulates with proximal end of phalanges.

Toes: made of long bones- phalanges. 2 phalanges (proximal, distal) in big toe (hallux). 3 phalanges (proximal, middle, distal) in each of other 4 toes. Lower Extremity/Limb - Arches

Ligaments and tendons hold bones in place  help in forming foot arches. Function: distribute/support body weight and provides balance while walking. Three arches: Medial horizontal arch Lateral horizontal arch Transverse arch Flat feet: arches never form. Less tolerance for long standing or walking (was issue with military service)