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Anatomy - NEETMDS- courses
NEET MDS Lessons
Anatomy

The Submandibular Glands

  • Each of these U-shaped salivary glands is about the size of a thumb and lies along the body of the mandible.
  • It is partly superior and partly inferior to the posterior 1/2 of the base of the mandible.
  • It is partly superficial and partly deep to the mylohyoid muscle.
  • The submandibular duct arises from the portion of the gland that lies between the mylohyoid and hyoglossus muscle.
  • The duct passes deep and then superficial to the lingual nerve.
  • It opens by one to three orifices on a small sublingual papilla beside the lingual frenulum.
  • The submandibular gland is supplied by parasympathetic, secretomotor fibres from the submandibular ganglion (preganglionic fibres from the chorda tympani via the lingual nerve).

Hip

Constitutes the pelvic girdle
United with the vertebral column
Union of three parts that is marked by a cup shaped cavity (acetabulum) Ilium
•    Prominence of the hip
•    Superior border is the crest
•    Anterosuperior spine-projection at the anterior tip of the crest
•    Corresponding projections on the posterior part are the posterosuperior and posteroinferior iliac spines
•    Greater sciatic notch-located beneath the posterior part
•    Most is a smooth concavity (iliac fossa)
•    Posteriorly it is rough and articulates with the sacrum in the formation of the sacroiliac joint

Pubic bone

Anterior part of the innominate bone
Symphysis pubic-joining of the two pubic bones at the midline
Body and two rami 
•    Body forms one fifth of the acetabulum
•    Superior ramis extends from the body to the median plane: superior border forms the pubic crest
•    Inferior ramus extends downward and meets with the ischium
•    Pubic arch is formed by the inferior rami of both pubic hones

Ischium
    Forms the lower and back part of the innominate bone
    Body
•    Forms two fifths of the accrabulum
•    Ischial tuberosiry-supports the body in a sitting position
•    Ramus-passes upward to join the inferior ramus of rhe pubis; known as rhe obturator foramen

Pelvis

Fanned by the right and left hip bones, sacrum, and coccyx

Greater pelvis

o    Bounded by the ilia and lower lumbar vertebrae
o    Gives support to the abdominal viscera

Lesser pelvis

o    Brim of the pelvis corresponds to the sacral promontory
o    Inferior outlet is bounded by the tip of the coccyx, ischial tuberosities, and inferior rami of the pubic bones

Female pelvis

o    Shows adaptations related to functions as a birth canal Wide outlet
o    Angle of the pubic arch is obtuse

Male pelvis

o    Shows adaptations that contribute to power and speed
o    Heart-shaped outlet
o    Angle of the pubic arch is acute


Thigh

Femur-longest and strongest bone of the body
Proximal end has a rounded head that articulates with the acetabulum
Constricted portion-the neck
Greater and lesser trochanters
Slightly arched shaft; is concave posteriorly
o    Linea aspera-strengthened by this prominent ridge
o    Site of attachment for several muscles
Distal end has two condyles separated on the posterior side by the intercondyloid notch

Knee cap

Patella-sesamoid bone
Embedded in the tendon of the quadriceps muscle
Articulates with the femur


Leg

Tibia-medial bone
o    Proximal end has two condyles that articulate with the femur
o    Triangular shaft

    Anterior-shin
    Posterior-soleal line
    Distal-medial malleolus that articulates with the latus to form the ankle joint
Fibula-lateral bone
o    Articulates with the lateral condyle of the tibia but does not enter the knee joint
o    Distal end projects as the lateral malleolus


Ankle, foot, and toes

Adapted for supporting weight but similar in structure to the hand

Talus

o    Occupies the uppennost and central position in the tarsus
o    Distributes the body weight from the tibia above to the other tarsal bones
Calcaneus (heel)-Iocated beneath the talus
Navicular-located in front of the talus on the medial side; articulates with three cuneifonn bones distally
Cuboid-lies along the lateral border of the navicular bone

Metatarsals
o    First, second, and third p1etatarsals lie in front of the three cuneifonn bones
o    (2) Fourth and fifth metatarsals lie in front of the cuboid bone

Phalanges

o    Distal to the metatarsals
o    (2) Two in the great toe; three in each of the other four toes .

Longitudinal arches in the foot (2)

o    Lateral-fonned by the calcaneus, talus, cuboid, and fourth and fifth metatarsal bones
o    Medial-fonned by the calcaneus, talus, navicular, cuneifonn, and first, second, and third metatarsal bones

Transverse arches-formed by the tarsal and metatarsal bones

 

MUSCLE

Types:

Skeletal (voluntary)
Cardiac (involuntary)
Smooth (involuntary)

Muscles of the Soft Palate

The Levator Veli Palatini (Levator Palati)

  • Superior attachment: cartilage of the auditory tube and petrous part of temporal bone.
  • Inferior attachment: palatine aponeurosis.
  • Innervation: pharyngeal branch of vagus via pharyngeal plexus.
  • This cylindrical muscle runs inferoanteriorly, spreading out in the soft palate, where it attaches to the superior surface of the palatine aponeurosis.
  • It elevates the soft palate, drawing it superiorly and posteriorly.
  • It also opens the auditory tube to equalise air pressure in the middle ear and pharynx.

 

The Tensor Veli Palatini (Tensor Palati)

  • Superior attachment: scaphoid fossa of medial pterygoid plate, spine of sphenoid bone, and cartilage of auditory tube.
  • Inferior attachment: palatine aponeurosis.
  • Innervation: medial pterygoid nerve (a branch of the mandibular nerve).
  • This thin, triangular muscle passes inferiorly, and hooks around the hamulus of the medial pterygoid plate.
  • It then inserts into the palatine aponeurosis.
  • This muscle tenses the soft palate by using the hamulus as a pulley.
  • It also pulls the membranous portion of the auditory tube open to equalise air pressure of the middle ear and pharynx.

 

The Palatoglossus Muscle

  • Superior attachment: palatine aponeurosis.
  • Inferior attachment: side of tongue.
  • Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
  • This muscle, covered by mucous membrane, forms the palatoglossal arch.
  • The palatoglossus elevates the posterior part of the tongue and draws the soft palate inferiorly onto the tongue.

 

  • Superior attachment: hard palatThe Palatopharyngeus Musclee and palatine aponeurosis.
  • Inferior attachment: lateral wall of pharynx.
  • Innervation: cranial part of accessory nerve (CN XI) through the pharyngeal branch of vagus (CN X) via the pharyngeal plexus.
  • This thin, flat muscle is covered with mucous membrane to form the palatopharyngeal arch.
  • It passes posteroinferiorly in this arch.
  • This muscle tenses the soft palate and pulls the walls of the pharynx superiorly, anteriorly and medially during swallowing.

 

The Musculus Uvulae

  • Superior attachment: posterior nasal spine and palatine aponeurosis.
  • Inferior attachment: mucosa of uvula.
  • Innervation: cranial part of accessory through the pharyngeal branch of vagus, via the pharyngeal plexus.
  • It passes posteriorly on each side of the median plane and inserts into the mucosa of the uvula.
  • When the muscle contracts, it shortens the uvula and pulls it superiorly.

The Orbital Margin

  • The frontal, maxillary and zygomatic bones contribute equally to the formation of the orbital margin.
  • The supraorbital margin is composed entirely of the frontal bone.
  • At the junction of its medial and middle thirds is the supraorbital foramen (sometimes a notch), which transmits the supraorbital nerves and vessels.
  • The lateral orbital margin is formed almost entirely of the frontal process of the zygomatic bone.
  • The infraorbital margin is formed by the zygomatic bone laterally and the maxilla medially.
  • The medial orbital margin is formed superiorly by the frontal bone and inferiorly by the lacrimal crest of the frontal process of the maxilla.
  • This margin is distinct in its inferior half only.

Digastric Muscle

  • Origin:
    • Anterior Belly: Digastric fossa of the mandible.
    • Posterior Belly: Mastoid notch of the temporal bone.
  • Insertion: Intermediate tendon attached to the body of the hyoid bone.
  • Nerve Supply:
    • Anterior Belly: Nerve to mylohyoid (branch of the trigeminal nerve, CN V3).
    • Posterior Belly: Facial nerve (CN VII).
  • Arterial Supply:
    • Anterior Belly: Branch of the submental artery.
    • Posterior Belly: Muscular branch of the posterior auricular artery and occipital artery.
  • Action: Raises the hyoid bone and base of the tongue, steadies the hyoid bone, and opens the mouth by lowering the mandible.

Superior Constrictor Muscle

  • Origin: Hamulus, pterygo-mandibular raphe, and mylohyoid line of the mandible.
  • Insertion: Median raphe of the pharynx.
  • Nerve Supply: Vagus nerve via the pharyngeal plexus.
  • Arterial Supply: Ascending pharyngeal artery, ascending palatine artery, tonsillar branch of the facial artery, and dorsal branch of the lingual artery.
  • Action: Constricts the wall of the pharynx during swallowing.

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