Flashcards in OCMM - Paired Bones Deck (42)
What are the 5 bony articulations of the parietal bone?
The ____ is the old mastoid fontanelle
The _____ is the old sphenoid fontanelle
The ____ bone is the only bone that contacts all 4 fontanelles
Which part of the parietal bone provides attachment point of temporal fascia?
Upper temporal ridge
Which part of the parietal bone is the origin of the temporalis m?
Lower temporal ridge
Which part of of the parietal bone is filled by temporalis m?
Describe the inner surface of the parietal bone
Contains sagittal sulcus (along sagittal suture in which sagittal sinus runs)
Groove of middle meningeal a. (Ant. and post)
There are bevel changes along coronal and lambdoidal articulations
Along lateral part is groove for transverse sinus which carries marginal insertion of tentorium cerebelli
There is a bevel change midway along the sagittal and lambdoidal sutures which creates a hinge for AP axis of motion (coronal plane). What motion occurs in the following parts of the paired bones with SBS flexion:
Pterion, asterion, and squamous sutures
Inferior borders move laterally
Superior borders move medially and inferiorly
Pterion, asterion, and squamous sutures move laterally
Sagittal suture moves slightly inferiorly
[this is external rotation; cranium widens laterally]
Signs and symptoms of parietal bone SD
Cranial synostosis (premature closure of sutures)
Head pain — pain along a suture
Middle meningeal a. trauma or giant cell arteritis
Head, face, or tooth pain patterns — temporal SD (TrP)
[OSCE says HA, alteration of seizure threshold, localized pain]
Parietal bone SD may manifest as head pain via pain along a suture. What sutures are often involved?
OM and asterion = often involved in tension headaches
Pterion = often involved in temporal headaches
Most common form of synostosis
Sagittal synostosis, accounting for about 50% of all cases
Premature fusion of the sagittal suture restricts the transverse growth of the skull
Form of synostosis most commonly mistaken for posterior positional deformational plagiocephaly
When unilateral, results in flattening of the back of the head on affected side as well as compensatory growth of mastoid process on the same side (ipsilateral mastoid bulge) — leads to characteristic ‘tilt’ in cranial base
The ear on the effected side is often deviated back and toward the fused suture
2 parts of temporal bone
Squamous portion — contains zygomatic process (affected in facial injury)
Petrous portion — contains otovestibular organ, eustachian tube exit is between sphenoid and temporal bones, border of foramen lacerum (with sphenoid) = greater superficial petrosal n. and lacrimation via pterygopalatine ganglion, attachment for tentorium, encloses internal carotid a., lateral part of jugular foramen, styloid process
What is unique about the temporal bone of a newborn skull?
Lacks a mastoid process
The mastoid process provides attachment for what muscles?
Internal rotation of the temporals may result in ____ pitched tinnitus
[Internal rotation places pressure on eustachian tubes leading to high pitched tinnitus; External rotation —> low roaring sound or low pitched tinnitus]
Temporal bone motion is driven by the ______ through ____ articulation
Describe external rotation of the temporal bone
Squamous portion moves laterally while mastoid process moves medially
Signs and symptoms of temporal bone SD
Head pain (OM/asterion, pterion, parietosquamous), neck pain d/t SCM or other muscle SD
Dizziness, ear infections, swallowing and chewing (stylohyoid, stylomandibular/TMJ, and styloglossus), tinnitus and eustachian tube dysfunction, bell’s palsy (CN VII)
[OSCE says OM, mastoiditis, tinnitus, hearing loss, dizziness, migraines, Bell’s, neuralgia; dysfunction can be caused by trauma, whiplash, chronic neck tension, dental extraction]
A 23 y/o male presents to the outpatient clinic with right sided head pain and ringing in his right ear 1 week after getting hit with a foul softball on top right side of the head. He was seen in the ER and dx with a grade 1 concussion after x-rays and PE found no neuro defects or fractures. The tinnitus started a day after his injury. MSK findings include:
Right mastoid process medial
Tenderness at point of injury
Right squamous area laterally prominent
What is the most likely temporal SD?
A. External rotation
B. Internal rotation
E. Superior vertical strain
A. External rotation
Frontal bone articulations
Describe external rotation of the frontal bone
Moves with hingelike motion as if still 2 bones (unfused metopic suture)
During SBS flexion (paired bone external rotation), lateral sides move anterior/lateral and slightly inferior, glabella moves posteriorly
What cranial bone is responsible for moving the frontal bone during external rotation?
Signs and symptoms of frontal bone SD
Head pain d/t pain along suture (coronal in tension headaches, pterion in temporal headaches), head pain d/t diminished PRM and CSF flow d/t increased dural tension at cribriform plate
Sinusitis (allergic or infectious), visual problems, anosmia (frontal influences cribriform plate), frontalis m. TrP/TP
[OSCE says HA, visual or smell disturbance (anosmia d/t ethmoid association), restriction can limit falx and all attachments; can get “wedged” from trauma]
Condition characterised by fusion of both coronal sutures leading to head shape called bracycephaly. Causes restriction of growth of anterior fossa resulting in a shorter and wider than normal skull. Compensatory vertical growth also occurs, called turricephaly
Often seen in pts wtih associated syndromes like Crouzon, Apert, Saethre-Chotzen, Muenke and Pfeiffer
What type of synostosis leads to head shape called anterior plagiocephaly?
Unicoronal synostosis — d/t premature fusion of a single coronal suture —> restricted anterior growth of the skull as well as cranial base
Causes deformities of the face, ear, nose, and forehead; affected forehead is flat with contralateral side more forward. Affected side ear also more forward. Face has characteristic C-shaped deformity (base of nose drawn toward affected side and tip of nose pointing away)
Axis and plane of motion associated with frontal bone
Dual AP axis in coronal plane
Superior/inferior axis in horizontal plane
[metopic suture has “hinge-like” property. Additionally, d/t location, inferior aspect travels more laterally and medially during flexion/extension (AP axis)]
Axis of temporal bone motion
Oblique axis from jugular surface to petrous apex — no exact plane (possibly modified coronal plane)
Axes of motion and plane associated with parietal bones
2 AP axes (one through each bone) — coronal plane