bone joint skeletal muscle

 

 1. arterial supply of youbg long bone

 2. sternal angle

 3. cartilaginous joint

 A. JOINT

Joint is the junction between two or more bones or cartilages. It allow different types of movement.

Joints are basically three types

 1. fibrous joints ( Immovable )

 2. Cartilaginous joints ( slightly movable)

 3. Synovial joints (freely movable)

CARTILAGINOUS JOINTS:-

 • bone are attached by cartilage

 • they are slightly movable

 • there are no joint cavity

 • there are two typs of cartilaginous joint:-

 a. Synchrondroses

 the bones joined by hyaline cartilage.

 eg:- Epiphyseal plate, Costal cartilage(to sternum)

 b. Symphyses

 the bones are joined by fibro cartilage .

 eg:- pubic symphysis, Intervertebral joints

SYNOVIAL JOINTS:-

Characeteristic features of synovial joints:-

 • has joint cavity between two bones

 • cavity is filled with synovial fluid, that helps lubricate and protect the bones

 • the part of the bone are covered with articular cartilage / hyaline cartilage

 • It has two capsule layers, outer fibrous capsule which is continuous with periosteum AND inner synovial membrane which secretes fluid.

 • it provides varying degree of movement.

 • they are diarthrosis

Types of synovial joints with eaxmple:-

There are 6 types of synovial joints , they are :-

 a. Ball and socket joint

 eg.:- Shoulder and hip joints

 b. Hinge joint

 eg:- Elbow and knee joints

 c. Pivot joint

 eg:- Proximal and distal radio ulner joint

 d. Gliding joints

 eg:- joint between carpal and tarsal bone.

 e. Saddle joints

 eg:- Wrist joint

 f. Condyloid joints

 eg:- metacarpo-phalangeal joint,

 metatarsal-phalangeal joint.

 B. BONE

TYPES OF BONE ON THE BASIS OF SHAPE/MORPHOLOGY:-

there are 6 types of bone on the basis of shape , they are:

 1. Long bone :-

 • they have elongated shaft known as diaphysis and two expanded ends known as epiphysis .

 • eg : Humerus, Femur, etc.

 2. Short Bones:-

 • these bones are short in posture and can be of any shape

 • eg: carpal and tarsal bones.

 3. Flat bones:-

 • they are flat in apperance.

 • eg: Scapula, Ribs, Sternum etc

 4. Irregular Bones :-

 • they are irregular in shape.

 • eg: vertebrae, hip bone, etc

 5. Pneumatic Bones

 • Bones containing air filled spaces

 • eg: Maxilla, sphenoid, ethmoid

 6. Sesamoid bone

 • these are nodules embedded in tendons , and joint capsules.

 • eg: Patella, Pisiform, fabella etc.

DIAGRAM OF LONG BONE/young long bone:-

ARTERIAL SUPPLY OF LONG BONE:-

Long bone is supplied by following arteries:-

 1. Nutrient artery:-

 • it enter the shaft thorugh nutrient foramen,

 • runs through cortex and on reaching medullary cavity , it divides into ascending and descending branches.

 • Each branch further divides into number of small parallel channels, and finaly terminat by anastomosig with periosteal, epiphyaseal and metaphyseal arteris.

 • it supplies medullary cavity and inner 2/3 of cortex.

 2. Periosteal arteries:-

 • these are numerous beneath the muscular and ligamentous attachments.

 • it enter the volkmann's canals to supply 1/3 rd of cortex.

 3. Epiphyseal arteries:-

 • they are derived from the peri-articular vascular arcades.

 • they supply epiphysis.

 4. Metaphyseal arteries

 • they are derived from neighbouring systemic vessels.

 • they supply metaphysis

 • metaphyseal arteries freely anastomose with branch of nutrient arteris , so metaphysis is the most vascualr area of long bone.

 C. CUBITAL FOSSA

this is an area of transition between the anatomical arm and the forearm, located as a depression on the anterior surface of elbow joint.

BOUNDARIES:-

The cubital fossa is triangular in shape , so it has three borders:

 • lateral border - medial border of the brachioradialis muscle.

 • medial border- lateral border of the pronator teres muscle.

 • superior border- hypothetical line between the epicondyles of the humerus.

 • FLOOR- it is created by 2 muscles , brachialis in the upper part and supinator in the lower part.

 • ROOF- it is created from superficial to deep by

 a. skin

 b. superficial fascia containig (i) median cubital vein attaching cephalic and basilic veins , (ii) medial and lateral cutaneous nerves of the forearm.

 c. deep fascia , reinforced by bicipital aponeurosis.

CONTENTS:-

from medial side to lateral side are as follows:

 • median nerve: it leaves the fossa by between 2 heads of pronator teres.

 • brachial artery : it bifurcates into the radial and ulnar arteries at the apex of fossa. it supplies oxygenated blood to forearm.

 • biceps tendon : it runs through the fossa, attache to the radial tuberosity , distal to the neck of radius.

 • radial nerve : it passes underneath the brachioradialis muscle, and divided into Superfical and deep branches.

@MBBS (mnemonic)

 D. FEMORAL TRIANGLE

It is a triangular depression on the front of the upper one-third of the thigh below the inguinal ligament.

Large neurovascular structures pass through this area , so it is an area of both anatomical and clinical importance.

BOUNDARIES:-

As this area is a triangle, it has three borders

 • superior border - formed by inguinal ligament , it forms the base of femoral triangle.

 • lateral border - formed by medial border of sartorius muscle.

 • medial border - fromed by medial border of adductor longus muscle.

 • apex - formed by meeting of sartorius and adductor longus muscle.

 • floor - is formed by ilio psoas lateraly and pectineus medialy.

 • roof- is fromed by fascia lata.

CONTAINS :-

the femoral triangle contains (lateral to medial) some of the major neurovascular structures of the lower limb, they are :

 • femoral nerve - it provides sensory branches for the leg and foot.

 • femoral artery - it supply to the lower limb.

 • femoral vein - the great saphenous vein drains into femoral vein within the triangle.

 • femoral canal - it contains deep lymph nodes and vessels.

@mneomonic @NAVL (NERVE, ARTERY, VEIN, LYMPH nodes)

 • ** the femoral artery , vein , and canal are contained within a fascial compartment , known as the femoral sheath.

 E. STERNAL ANGLE

The sternal angle (angle of Louis) is the anterior angle formed by the junction of the manubrium and the body of the sternum.

The sternal angle is a palpable clinical landmark under the skin that marks a numbers of other anatomical events, such as :-

 • it is located at the level of intervertebral disc between T4 and T5 vertebrae.

 • Boundary between the superior and inferior mediastinum

 • Ascending aorta finishes at this level.

 • Arch of aorta starts and finish at this level.

 • Descending aorta starts at this level.

 • Tracheal Bifurcation into right and left main bronchi at this level.

 • pulmonary trunk splits into left and right pulmonary arteries at this level

 • upper border of heart is located at this level.

 • azygos vein arches over the root of right lung to finish in the Superior venacava.

 F. Classification of skeletal muscle accorinding to FASCICULAR architecture:-

There are following types :

 1. Parallel Fasciculi :- when the fasciculi are parallel to the line of pull. they are classified as :-

 • quadrilateral ,eg: thyrohyoid

 • straplike, eg: sternohyoid, sartorius

 • strap-like with tendinous intersections eg: rectus abdominis

 • fusiform , eg: biceps , digastric

 2. Oblique Fasciculi :-

 • triangular , eg: adductor longus

 • fan shaped , eg: temporalis

 3. Pennate Fasciculi

 • unipennate, eg: flexor pollics longus, extensor digitorum longus, peroneus tertius

 • Bipennate ,eg : rectus femoris , dorsal interossei, peroneus longus, flexor hallucis longus

 • multipennate, eg: deltoid , subscapularis

 • Circumpennate, eg: tibialis anterior

 4. Spiral or Twisted Fasciculi

 • Spiral fibres ,eg: trapezius, latissimus dorsi, pectoralis major , supinator etc.

 • Cruciate fibres , eg: sternocleidomastoid , masseter, adductor magnus